Inactivation of the waterborne marine pathogen Vibrio alginolyticus by photo-chemical processes driven by UV-A, UV-B, or UV-C LED combined with H2O2 or HSO5

Javier Moreno-Andrés; Miguel Tierno-Galán; Leonardo Romero-Martínez; Asunción Acevedo-Merino; Enrique Nebot

doi:10.1016/j.watres.2023.119686

Inactivation of the waterborne marine pathogen Vibrio alginolyticus by photo-chemical processes driven by UV-A, UV-B, or UV-C LED combined with H₂O₂ or HSO₅

Water Res. 2023 Apr 1:232:119686. doi: 10.1016/j.watres.2023.119686. Epub 2023 Jan 31.

Authors

Javier Moreno-Andrés¹, Miguel Tierno-Galán², Leonardo Romero-Martínez², Asunción Acevedo-Merino², Enrique Nebot²

Affiliations

¹ Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR-Marine Research Institute, CEIMAR- International Campus of Excellence of the Sea. University of Cadiz, Spain. Electronic address: javier.moreno@uca.es.
² Department of Environmental Technologies, Faculty of Marine and Environmental Sciences. INMAR-Marine Research Institute, CEIMAR- International Campus of Excellence of the Sea. University of Cadiz, Spain.

PMID: 36764105
DOI: 10.1016/j.watres.2023.119686

Abstract

Ultraviolet (UV) radiation is a well-implemented process for water disinfection. The development of emergent UV sources, such as light-emitting diodes (LEDs), has afforded new possibilities for advanced oxidation processes. The emission wavelength is considered to be an important factor for photo-chemical processes in terms of both biological damage and energetic efficiency, as the inactivation mechanisms and mode-of-action may differ according to the wavelength that is applied. In addition, these processes merit exploration for inactivating emerging pathogens, such as marine vibrios, that are important bacteria to control in maritime activities. The main goal of this study was to compare the disinfection efficacy of several UV-LED driven processes with different modes of action. First, the effect of UV-LEDs was assessed at different UV ranges (UV-A, UV-B, or UV-C). Second, the possible enhancement of a combination with hydrogen peroxide (H₂O₂) or peroxymonosulfate salt (HSO₅^-) was investigated under two different application strategies, i.e. simultaneous or sequential. The results obtained indicate a high sensitivity of Vibrio alginolyticus to UV radiation, especially under UV-B (k_obs = 0.24 cm²/mJ) and UV-C (k_obs = 1.47 cm²/mJ) irradiation. The highest inactivation rate constants were obtained for UV/HSO₅^- (k_obs (cm²/mJ)=0.0007 (UV-A); 0.39 (UV-B); 1.79 (UV-C)) with respect to UV/H₂O₂ (k_obs (cm²/mJ)=0.0006 (UV-A); 0.26 (UV-B); and 1.54 (UV-C)) processes, however, regrowth was avoided only with UV/H₂O₂. Additionally, the disinfection enhancement caused by a chemical addition was more evident in the order UV-A > UV-B > UV-C. By applying H₂O₂ (10 mg/L) or HSO₅^- (2.5 mg/L) in a sequential mode before the UV, negligible effects were obtained in comparison with the simultaneous application. Finally, promising electrical energy per order (EE_O) values were obtained as follows: UV/HSO₅^- (EE_O (kWh/m³)=1.68 (UV-A); 0.20 (UV-B); 0.04 (UV-C)) and UV/H₂O₂ (EE_O (kWh/m³)=2.15 (UV-A); 0.32 (UV-B); 0.04 (UV-C)), demonstrating the potential of UV-LEDs for disinfection in particular activities such as the aquaculture industry or maritime transport.

Keywords: Aquaculture; Ballast water; LED; Marine bacteria; Reactivation; Ultraviolet.

MeSH terms

Disinfection / methods
Hydrogen Peroxide* / pharmacology
Photochemical Processes
Ultraviolet Rays
Vibrio alginolyticus
Water Purification* / methods

Substances

Hydrogen Peroxide